1. Technical Field
The present invention relates to a radiographic image capturing device.
2. Related Art
In recent years, radiation detectors such as flat panel detectors (FPD) that comprise a radiation-sensitive layer placed on a thin-film transistor (TFT) active matrix substrate, detect radiation such as X-rays with which the radiation detector has been irradiated, and output electrical signals representing a radiographic image expressed by the detected radiation have been put to practical use. These radiation detectors have advantages in that, as compared to conventional imaging plates, images can be checked instantaneously and videos can also be checked. As systems of converting radiation in radiation detectors, there are an indirect conversion system, in which a scintillator is used to convert the radiation into light and then a semiconductor layer such as a photodiode is used to convert the light into electric charges, and a direct conversion system, in which a semiconductor layer such as amorphous selenium is used to convert the radiation into electric charges; in each system, there exist various materials that can be used for the semiconductor layer.
Portable radiographic imaging devices (also called “electronic cassettes” below) into which such radiation detectors are built and which store radiographic image data outputted from the radiation detector have also been put to practical use.
Incidentally, fluoroscopy, in which video imaging is performed, consumes a lot of electrical power because the imaging operation is repeated continuously. For this reason, there is a wired connection type of electronic cassette that is used by connecting the electronic cassette via a cable to a control-use terminal (a so-called console) for performing stable electrical power supply or data transfer.
However, with the wired connection type of electronic cassette, there are cases where various types of noise are transmitted via the cable and the noise ends up rising on the image data.
Thus, in Japanese Patent Application Laid-Open (JP-A) No. 2008-17021, there is described a technology where, in a radiographic image capturing system having a wireless power feed device, wireless power feeding is prohibited at the time of imaging.
Further, in JP-A No. 2009-50689, there is a technology where, in regard to a radiographic image capturing system having a wireless communication device, imaging and wireless communication are not performed at the same time and supply of electrical power supply from an outside power source is shut off by wireless communication to eliminate the influence of power source noise.
It is conceivable to utilize the technologies described in JP-A No. 2008-17021 and JP-A No. 2009-50689 to house a built-in battery in the electronic cassette, shut off supply of electrical power via the cable at the time of fluoroscopy, and perform supply of electrical power from the built-in battery.
However, as mentioned above, fluoroscopy consumes a lot of electrical power, so in a case where supply of electrical power via a communication cable is shut off at the time of imaging and supply of electrical power is performed from a built-in battery, the period in which a video can be captured is short.